Liquid spraying apparatus



March 2, 1965 E. w. ECKEY 3,171,600

LIQUID SPRAYING APPARATUS Filed Dec. 31, 1962 4 Sheets-$heet 1 TNVENT OREdagyWIc/z'g ATTORNEY;

Mamh 1965 E. w. ECKEY 3,171,600

LIQUID SPRAYING APPARATUS Filed Dec. 31, 1962 4 Sheets-Sheet 2 INVENTOREahfy WI [63 5}! ATTORNEY)- March 2, 1965 w. ECKEY LIQUID SPRAYINGAPPARATUS 4 Sheets-Sheet 3 Filed Dec. 31, 1962 LL, M M,%

ATTORNEYS March 2, 1965 E. w. ECKEY 3,171,600

LIQUID SPRAYING APPARATUS Filed Dec. 31, 1962 4 Sheets-Sheet 4 INVENTOREdg WEckey ATTORNEY$ United States Patent Ofiice 3,171,6dh Patented Mar.2, 1965 3,171,600 LIQUID SPRAYING APPARATUS Eddy W. Eckey, 313 S. WayneAve, Cincinnati, Ohio Filed Dec. 31, 1962, Ser. No. 248,578 19 Claims.(Cl. 239-220) This invention relates to liquid spraying apparatus andmore particularly to such apparatus utilizing rotatable impellers forcentrifugally projecting a spray of liquid.

This application is a continuing application based in part on myco-pending application Serial No. 216,008, filed July 23, 1962, which isa continuation-in-part of application Serial No. 788,432, filed January22, 1959, now abandoned, which in turn is a continuation-in-part ofapplication Serial No. 616,161, filed October 16, 1956 now abandoned.

In general the present invention is useful wherever a spray of liquid isrequired. One primary field of utility resides in apparatus forprojecting one or more sprays of liquid across a moving stream of gas tomake repeated renewal of large areas of fresh liquid surfaces to effectintimate contact with the gas.

The liquid spraying impellers which heretofore have been available tothe art have been characterized by a variety of disadvantages. Forexample, rotating discs with teeth or scoops on their periphery do notmove sufficient liquid when operated at slow speed and at high speedsthey tend to create a mist which becomes entrained in a moving stream ofgas. Moreover, at any speed, such impellers tend to project a highlynon-uniform spray with most of the output limited to the rising side ofthe impeller.

It has also been proposed to utilize a hollow impeller having a thinperforated wall at its periphery so that liquid may be admitted in anaxial direction inside of the hollow impeller and projected bycentrifugal force outwardly through the thin perforated rim. Knownstructures of this type, however, have not retained sufiicient liquid inthe impeller over its entire periphery to effect a substantially uniformspray from all points on the ex posed periphery. Moreover, suchstructures have been characterized by low capacity and lack of controlof the velocity and droplet size of the spray.

To overcome the disadvantages of the prior art, an object of the presentinvention is to provide a liquid spraying apparatus utilizing a highcapacity rotary impeller winch projects a copious uniform spray atvelocities and droplet sizes within acceptable limits.

Another object of the invention is to provide such an apparatus whichnot only has high performance capabilities but is inexpensive to makeand use.

In general, the invention relates to a liquid spraying apparatus whichcomprises a rotatable impeller having a cavity inside of said impeller,an annular rim bordering said cavity and an opening in an end face ofsaid impeller to admit liquid into said cavity, and means in said rim toreceive a substantial volume of liquid from said cavity and to retardand effect a plurality of direction changes in the outward centrifugalflow of said liquid when the impeller is rotated so that said liquid issprayed substantially uniformly from the entire exposed periphery ofsaid impeller, said means including a plurality of elongated tortuouspassages extending through said rim to connect said cavity with saidperiphery.

The invention having been generally described several illustrativespecific embodiments thereof will now be set forth in detail withreference to the accompanying drawings in which:

FIGURE 1 is a vertical section taken longitudinally through a gas-liquidcontact device embodying apparatus according to the invention;

FIGURE 2 is a fragmentary front detail showing of an impeller disc andillustrating the relationship between two adjoining discs;

FIGURE 3 is a View similar to FIGURE 2 showing a portion of one of theouter impeller discs;

FIGURE 4 is a fragmentary vertical section taken through the impellerrim showing the flow path through the impeller discs;

FIGURE 5 is a fragmentary front detail of a modified form of inner disc;

FIGURE 6 is a fragmentary front detail of a modified form of outer disc;

FIGURE 7 is a fragmentary front detail of a still further modified formof inner disc;

FIGURE 8 is a vertical section showing the cooperation between and theflow path through the impeller discs of FIGURES 5 and 6;

FIGURE 9 is a vertical section taken through a modified form of impellerutilizing alternating wide and narrow discs with the latter whollyinside of the former;

FIGURE 10 is a fragmentary front detail of a pair of adjoining wide andnarrow dscs of FIGURE 9;

FIGURE 11 is a vertical section taken through the impeller of FIGURE 9showing the cooperation between and liquid flow through the impellerdiscs;

FIGURE 12 is a plan view of a trough which surrounds the lower portionof the impeller;

FIGURE 13 is a vertical section taken along the line 13-13 of FIGURE 12;

FIGURE 14 is a transverse vertical section showing an impeller accordingto the invention mounted in a gasliquid contact tube and illustratingthe uniform spray pattern which is produced;

FIGURE 15 is a vertical section taken through still another modifiedform of impeller;

FIGURE 16 is an end View of the shaft connection for the impeller shownin FIGURE 15;

FIGURE 17 is a fragmentary front detail of a pair of adjoining wide andnarrow discs of the impeller of FIG- URE 15; and

FIGURE 18 is a vertical section showing the cooperation between and theflow path through the impeller discs of FIGURES 15-17.

Illustrated in FIGURE 1 is a fragmentary section of an elongatedhorizontal tube II which forms a part of a gas-liquid contact apparatusas fully shown and described in my said co-pending application SerialNo. 216,008, the disclosure of which is incorporated herein byreference. While it is not necessary to repeat here all of the detailsof such gas-liquid contact apparatus, a brief explanation shouldfacilitate a better understanding of the present invention.

A cross sectional view of the tube 11 is shown in FIG- URE 14. Mountedin the lower portion of the tube are a plurality of horizontally spacedimpellers 12, only one of which is shown. Each impeller 12 is fixed to ashaft 13 which extends longitudinally in the tube 11 and is journalledfor rotation in suitable bearings at opposite ends of the tube. Theshaft and impellers are positioned in the lower portion of the tube 11so as to leave in the upper portion of the tube a large crescent shapedpassageway 14 (FIGURE 14) through which gas to be contacted is movedhorizontally as more fully described in application Serial No. 216,008.The impellers 12 when they are rotated project a plurality of spacedspray curtains of liquid across'the passageway 14 for intimate contactwith the gases flowing therethrough. Preferably, as described in saidcopending application, the flow of liquid in the tube from impeller toimpeller is countercurrent to the flow of gas through the tube. Theliquid after being sprayed across the passageway 14 coalesces on theupper and side walls of the tube 11 and flows downwardly to the bottomof the tube between guide members 15. A portion of the returning liquidis directed downstream to the next succeeding impeller and anotherportion is returned to the same impeller from which it was lastprojected. Various specific arrangements as shown in application SerialNo. 216,008 may be utlilized to control the extent of recirculation ofliquid after projection from the individual impellers.

Each of the impellers 12 includes a front plate 16 and a back plate 17which is fixed to the shaft 13 by tapered split rings 18 .and threadedfasteners 19. However, other suitable means may be employed to connectthe impeller to the shaft instead of the specific arrangement shown inFIGURE 1. The impeller 12 is hollow with a large opening 20 in its frontface leading into a large cavity 21 which extends between the shaft 13and the impeller rim 22. When the impeller is in use, liquid flowsaxially through the opening 20 into the lower portion of the cavity 21.The rim 22 has its front face formed by the front plate 16 and includesa plurality of overlapping inner plates in the form of annular discs 23and outer plates in the form of annular discs 24 which are connected tocontiguous face-to-face relationship between the plates 16 and 17 byrivets 25 or other suitable fasteners.

Each of the inner discs 23 has a series of holes 26 on an inner portionof the disc and a second plurality of holes 27 in an outer portion ofthe disc. The outer discs 24 have a series of spaced holes 28. The holes26, 27 and 28 preferably consist of through openings uniformly spacedaround the entire circumference of their respective discs. The openings27 and 28 may take the form of elongated slots having scalloped 'edgesas shown in FIGURES 2 and 3 which slots are inclined outwardly in thedirection of rotation of the impeller. As best shown in FIGURE 4 theinside radius of each of the outer discs 24 is slightly greater than theradius of a circle coinciding with the inner ends of the openings 27 inthe inner discs 23. Thus an elongated straight passage 31 is definedbetween each adjoining spaced pair of discs 23, such passage extend-ingfrom the inner edge of such discs 23 to the inner edge of the disc 24which is held between the discs 23. The passages 32 form continuousannular channels and are substantially unobstructed through their radiallength. Because the inner edge of the disc 24 is outwardly of the inneredge of the openings 27 in the disc 23, liquid is free to flow from thecavity 21 outwardly through the passages 31 and then axially into theopenings 27 on both sides of the inner edge of each disc 24. Such flowis illustrated in FIGURE 4 and occurs as a result of centrifugal forcewhen the impeller is rotated. The inner edge of the openings 28 arepositioned radially inwardly of the outer edge of the openings 27.Consequently, the liquid is free to flow from the openings 27 into theopenings 28 in .an axial direction opposite to that in which it flowedinto the openings 27. The radially outer edge of the openings 28 arepositioned outwardly of the radially outer edge of the disc 23.Accordingly, the liquid in the openings 28 again reverses its axialdirection and flows into channels 32 which lie between the discs 24outwardly of the discs 23. Probably most of the liquid flow in thechannels 32 is along the faces of the outer edges of the discs 24 fromwhich the liquid is projected tangentially outwardly from the peripheryof the impeller.

It can thus be seen that the relationship between the perforated discs23 and 24 including the overlapped staggered relation of the openings 27and 28 provides a plurality of elongated tortuous passages extendingthrough the rim of the impeller to connect the cavity 21 with theimpeller periphery. A substantial volume of liquid may be received inthe passages between the discs and, as such liquid moves centrifugallyoutwardly it is forced to undergo a plurality of direction changes. Thetortuous path throught the impeller rim sufliciently retards the flow ofliquid to afford the impeller time to rotate a substantial distancewhile the liquid is passing from the cavity to the periphery of theimpeller. Such retardation of flow results in the projection of asubstantially uniform spray pattern from the entire exposed periphery ofthe impeller 12 as illustrated in FIGURE 14. In the absence of suchretardation, most of the liquid would be projected on the rising side ofthe impeller and there would be little liquid left to be projected fromthe top or thedescending side of the impeller. As a result the spraypattern would be concentrated in the lower left hand corner of thepassageway 14 as shown in FIGURE 14.

Moreover, the liquid is projected as droplets of a sufficient size as tobe substantially non-entraining in a moving stream of gas in thepassageway 14. Manifestly, droplet size will vary depending upon suchfactors as the particular size of the openings in the discs, the spacingbetween the discs and the speed of rotation of the impeller. Increasedspeed of a given impeller structure increases the fineness of the spray.Very fine spray is not necessary or desirable. A characteristic of thespray produced with this apparauts is that the droplet sizes for anyparticular operating condition are relatively uniform as compared withthe non-uniform size distribution in sprays produced by other means suchas high pressure spray nozzles or the like. It has been found thatdroplet sizes within the range from 0.1 mm. to 2 mm. in diameter aresatisfactory for most operations.

The desired droplet size can be obtained when using impellers of aparticular size and design by operating the impellers at an appropriatespeed of rotation. Impellers of different diameters produceapproximately equivalent sprays when operated respectively atthe sameperipheral velocity. The preferred range of speeds of rotation is suchthat the values of penipheral velocity in feet per second lie in therange between 18 and 50. Below this range the spray is not sufficientlyenergetic and uniform to make a good spray pattern across the hollowvapor space. Above this range the spray impinges too violently on thetube wall with a resulting tendency to production of the fine lateralspray and entraining in the stream of vapor. Moreover, power consumptionbecomes undesirably high above the preferred range. Especially preferredis a peripheral velocity range between 25 and 40 feet per second.

It has been found that provision of a relatively straight passage, suchas the channels 31, immediately after the liquid leaves the impellercavities is desirable to permit rapid acceptance of large quantities ofliquid into the impellers. Thus, the inner edges of the discs24, whichmark the beginning of the tortuous portion of the liquid path throughthe impeller rim, preferably .arespaced outwardly of the inner ends ofthe discs 23. For certain operations, however, a passageway tortuousthroughout the impeller rim would be satisfactory.

Further, if desired, the perforations 26 in the discs 23 may be omitted.It has been found, however, that better performance occurs when suchperforations are utilized. Apparently the perforations 26 provide anadditional storage compartment for the liquid thus enabling greater andfastener acceptance of liquid by the rim of the impeller from thecavity. Such perforations also provide communication between thepassages 31 thereby facilitate ing equalization of flow through the rimamong the different passages. Moreover, the perforations 26 tend toincrease the turbulence of flow through the passages 31 as illustratedin FIGURE 4.

The lower portion of the impeller 12 is enclosed in a trough 41 whichclosely surrounds the impeller. The trough 41 has a front wall 42, arear wall 43 and a generally arcuate bottom 44 to conform generally tothe peripheral configuration of the impeller. The front wall 42 isprovided with a weir 45 which preferably has an arcuate configurationcorresponding to the arcuate shape of the interior of the rim 22. Inother words, the weir 45 and the opening 20 into the cavity 21 of theimpeller,

preferably have the same radius and are coaxial with each other. Thus,liquid flowing across the weir 45 is smoothly directed into the cavity21 for projection by the impeller in the manner previously described.However, it is not essential that the respective shapes of the weir andthe impeller opening be identical. Indeed, the trough opening need notnecessarily be a weir. For example, an orifice could be employed.

Desirably the periphery of the impeller eifects little or no exteriorpickup of liquid from inside of the trough 41. Substantially all of theliquid which is sprayed is that which is deposited inside of theimpeller cavity and moves centrifugally outwardly through the elongatedtortuous passages in the impeller rim.

Preferably the bottom 44 of the trough 4-1 is flared away from theimpeller periphery on the outlet side of the impeller as shown at 4.6 inFIGURES 13 and 14. The flare 46 allows more effective removal from thetrough of the liquid that has been sprayed into the trough by theimpeller. Moreover, the flared portion 45 prevents overloading of theimpeller with liquid as it emerges from the trough. Further, it has beenfound that performance is improved where one or more narrow vanesextending in the direction of movement of the impeller are positioned atspaced locations in the bottom of the flared portion 46 of the trough.In the illustrated embodiment of the trough a plurality of such vanes 47are employed. The use of such vane or vanes further facilitates handlingthe excess liquid which is sprayed from the impeller into the trough.

Modified forms of impeller discs are shown in FIG- URES 5 and 6. Thedisc 123 shown in FIGURE 5 corresponds to the disc 23 and the disc 124shown in FIG- URE 6 corresponds to the disc 24. The discs 123 and 124are identical to their counterparts 23 and 24 except that the former arecharacterized by a plurality of pairs of round openings spaced apart onradial lines, rather than single inclined slots, in their overlappingportions. Specifically, the disc 123 has pairs of spaced openings 127and 127. The disc 124 has pairs of spaced openings 128 and 128'. Theopenings 127 and 127 in the discs 123 are placed in overlappingstaggered relation with the openings 128 and 128 of the discs I24 in thesame general relationship as that between the openings 27 and 28 toprovide a tortuous passageway for the centrifugal flow of liquid throughthe impeller rim.

It will be understood that the openings in any of the various forms ofdiscs illustrated herein are not limited to any particular shape such asthe elongated slots as shown in FIGURES 2 and 3 or the circular openingsshown in FIGURES 5 and 6. A variety of other shapes may be utilized. Forexample, the openings may be substantially square with rounded edge asshown at 228 and 228' in FIGURE 7. Indeed, the particular configurationshown in FIGURE 7 is preferred.

In the embodiments described thus far there have been one set of innerdiscs and an overlapping set of outer discs which extend radiallyoutwardly beyond the outer edges of the inner discs. If desired,however, there may be one set of very wide discs 323 and one set of verynarrow discs 324 as illustrated in FIGURES 9, l0 and 11. In thisarrangement the discs 3Z3 extend beyond the discs 324 on both theradially inner and outer edges of the latter. The overlapping staggeredrelation between the openings in the discs 324- and 323 is the same asthat of the previously described embodiments.

A further modified form of impeller which is simple to fabricate yethighly effective is shown in FIGURES 1S18. The back plate 417 of suchimpeller is mounted to the shaft 13 by a connection alternative to thatof FIGURE 9. Either of these connections or others may be employed withrespect to any of the various impeller embodiments. The shaft 13 has acircumferential ridge 559 which may be integral with the shaft or takethe form of an inserted key. This ridge may encompass all or a portionof the circumference of the shaft. A pair of mating annular rings 551and 552 are connected together by a series of threaded fasteners 553 togrip the protrusion 55% between the rings. The inside face of ring 552is shown in FIGURE 16. The outer edges of the rings 551 and 552 grip theinner end of the back plate 4-17, which is grooved to receive the disc552 and a spacer 554.

The impeller shown in FIGURES 15-18 like that of FIGURE 9, has aplurality of very wide discs 423 and a plurality of narrow discs 424.The discs 423 extend be yond both the radially inner and outer edges ofthe discs 224-. Unlike any of the previously described inner discs,however, the discs 424 are continuous and unperforated except for holesaccommodating the rivets 425. In order to carry liquid radially past thediscs 424, the discs 423 are provided with a plurality of elongatedslots 428 which extend radially beyond both edges of the discs 424.Thus, as shown in FIGURE 18, liquid is free to bypass the discs 424 byflowing in a tortuous path into, through and out of the slots 428. Asshown in FIGURE 17, the slots 42% are inclined outwardly in thedirection of rotation of the impeller. The slots 428 also have scallopededges, best seen in FIGURE 17, which increase the resistance to flowthrough the slots. The irregular or scalloped edges of the slots providea marked improvement in the performance of the impeller.

The discs 423 are also provided inwardly of the discs 424 with openings426 which have the same function as the openings as of the discs shownin FIGURES 1-4.

There have been shown and described what are considered to beillustrative embodiments of the invention. It will be understood,however, that various modifications may be made by persons skilled inthe art without departing from the scope of the invention which isdefined solely by the appended claims.

I claim:

1. An apparatus for spraying a curtain of liquid droplets through astream of moving gas which comprises a. rotatable impeller, meanssupporting said impeller for rotation about a generally horizontal axis,said impeller having a cavity inside thereof, a pair of spaced platesdefining tront and rear faces of said impeller, said front platedefining an inlet to admit liquid axially into said cavity, a pluralityof contiguous members positioned betweensaid plates to form a rimoutside of said cavity, said plates and said members being connectedtogether against rotation relative to each other, said members defininga plurality of elongated tortuous passages extending through said rimfrom said cavity to the impeller periphcry to retard and effect aplurality of direction changes in the outward and upward centrifugalflow of said liquid when the impeller is rotated so that saidliquid issprayed substantially uniformly from the entire exposed periphery ofsaid impeller, said passages including openings in at least some of saidmembers extending transverse to radial direction.

2. An apparatus as recited in claim 1 further comprising a troughsurrounding the lower portion of said impeller, said trough having anaxial inlet in communication with said impeller inlet.

3. An apparatus as recited in claim 2 wherein said passages havestraight inner portions and tortuous outer portions.

4. An apparatus as recited in claim 2 further comprising means to rotatesaid impeller at a velocity relative to the size of said passages toemit droplets of sufficient size to be substantially nonentrained in themoving gas.

5. An apparatus as recited in claim 4 wherein said rotating means movessaid impeller at a peripheral velocity from 18 to 50 feet per second.

6. An apparatus as recited in claim 4 wherein said rotating means movessaid impeller at a velocity to project droplets having a diameter offrom 0.1 to 2 mm.

7. An apparatus as recited in claim 4 wherein the bottom of said troughgenerally conforms to the peripheral configuration of said impeller,said bottom flaring away from the impeller periphery at the outlet sideof said trough, said flared portion of said bottom having elongated vanemeans thereon parallel to the rotational movement of the impeller.

8. An apparatus as recited'in calim 4 wherein said passages havestraight inner portions and tortuous outer portions.

9. A liquid spraying apparatus which comprises a rota able impellerhaving a generally horizontal axis of rotation, said impeller having acavity inside of said impeller,

an'opening in an end face of said impeller to admit liquid axially intosaid cavity, and

an annular rim bordering said cavity, said rim including a plurality ofspaced plates defining generally radial passages for centrifugal flow ofliquid when said impeller is rotated, said passages being substantiallystraight over an inner portion of said plates, at least an outer portionof said plates having transverse holes therein, and

means radiallyspaced from the inner edges of said plates and situatedbetween said outer portions and cooperating with said holes todirect theliquid in tortuous paths extending into said holes and to retard theflow of said liquid to the outer periphery of said impeller so that saidliquid is sprayed substantially uniformly from the entire exposedperiphery of said impeller.

10. An apparatus as recited in claim 9 wherein said plates compriseannular discs lying in a plane transverse to the axis of rotation ofsaid impeller and said means comprises a plurality of annular discshaving a larger inside diameter than said plates and a plurality oftransverse holes in overlapped staggered relation with said holes insaid plates.

11. A liquid spraying apparatus which comprises an impeller rotatableabout a generally horizontal axis,

said impeller having a cavity inside of said impeler,

an opening in an end face of said impeller to admit liquid axially intosaid cavity, and

an annular rim bordering said cavity, said rim including a plurality ofspaced plates defining generally radial passages for centrifugal flow ofliquid when said impeller is rotated, said passages being substantiallystraight over an inner portion of said plates, at least an outer portionof said plates having trans verse holes therein, and means radiallyspaced from the inner edges of said plates and situated between saidouter portions and cooperating with said holes to direct the liquid intortuous paths extending into said holes and to retard the flow of saidliquid to the outer periphery of said impeller so that said liquid issprayed substantially unformly from the entire exposed periphery of saidimpeller, and a trough having 18. bottom andupright walls surroundingthe lower portion of said impeller and an inlet in communication withsaid impeller opening. 12. An apparatus as recited in claim 11 whereinsaid plates comprise annular discs lying in a plane trans verse to theaxis of rotation of said impeller and said means comprise a plurality ofannular discs having a larger inside diameter than said plates and aplurality of transverse holes in overlapped staggered relation with saidholes in said plates.

13. An apparatus as recited in claim. 11 wherein the bottom of saidtrough generally conforms .to the peripheral configuration of saidimpeller, said bottom flaring away from the impeller periphery at theoutlet side ofv said trough.

14. An apparatus as recited in claim 12 wherein the bottom of saidtrough generally conforms to the peripheral'configuration of saidimpeller, said bottom flaring away from the impeller periphery at theoutlet side of said trough.

15. An apparatus as recited in claim 13 wherein the flared portion ofsaid bottom has vane means thereon parallel to the rotational movementof the impeller.

16. An apparatus as recited in claim 14 wherein the flared portion ofsaid bottom has vane means thereon parallel. to the rotational movementof the impeller.

17. A liquid spraying apparatus which comprises a rotatable impellerhaving a generally horizontal axis of rotation, said impeller having a.cavity inside of said impeller,

an opening in an end'face of said impeller to admit liquid into saidcavity, and

an annular rim bordering said cavity, said rim including a plurality ofcontiguous plates, adjoining ones of said plates having overlappedstaggered transverse holes to provide a plurality of tortuous passagesextending generally radially through said rim to connect said cavitywith said periphery so that when said impeler is rotated centrifugalflow of liquid through said passages'is retarded to provide asubstantially uniform spray from the entire exposed periphery of saidimpeller.

18. A liquid spraying apparatus as recited in claim 17 wherein saidplates comprise annular discs lying in a plane transverse to the axis ofrotation of said impeller.

19. A liquid'spraying apparatus which comprises an impeller rotatableabout a generally horizontal axis,

said impeler having a cavity inside of said impeller, an opening in-anend face of said impeller to admit liquid axially into said cavity, andan annular rim bordering said cavity, said rim including a plurality ofcontiguous annulardiscs adjoining ones of said discs having overlappedstaggered transverse holes to provide a plurality of tortuous passagesextending generally radially through said rim to connect said cavitywith said periphery'so that when said impeller is rotatedcentrifugalflow of liquid through said passages is retarded to provide asubstantially unform spray from the entire exposed periphery of saidimpeller, and a trough having i 1 a bottom and upright walls surroundingthe lower portion or" said impeller and an inlet in communication withsaid impeller openmg.

References Cited by the Examiner UNITED STATES PATENTS 1,667,291 4/28Lavett 239-220 1,870,099 8/32 Croan 239-223 1,948,278 2/34 Payne et a1.239-22O 2,959,357 11/60 Geller 239220 FOREIGN PATENTS 761,881 1/34France. 876,066 V 8/61 Great Britain.

LOUIS}. DEMBO, Primary Examiner. EVERETT W. KIRBY, Examiner.

1. AN APPARATUS FOR SPRAYING A CURTAIN OF LIQUID DROPLETS THROUGH ASTREAM OF MOVING GAS WHICH COMPRISES A ROTATABLE IMPELLER, MEANSSUPPORTING SAID IMPELLER FOR ROTATION ABOUT A GENERALLY HORIZONTAL AXIS,SAID IMPELLER HAVING A CAVITY INSIDE THEREOF, A PAIR OF SPACED PLATESDEFINING FRONT AND REAR FACES OF SAID IMPELLER, SAID FRONT PLATEDEFINING AN INLET TO ADMIT LIQUID AXIALLY INTO SAID CAVITY, A PLURALITYOF CONTIGUOUS MEMBERS POSITIONED BETWEEN SAID PLATES TO FORM A RIMOUTSIDE OF SAID CAVITY, SAID PLATES AND SAID MEMBERS BEING CONNECTEDTOGETHER AGAINST ROTATION RELATIVE TO EACH OTHER, SAID MEMBERS DEFININGA PLURALITY OF ELONGATED TORTUOUS PASSAGES EXTENDING THROUGH SAID RIMFROM SAID CAVITY TO THE IMPELLER PERIPHERY TO RETARD AND EFFECT APLURALITY OF DIRECTION CHANGES IN THE OUTWARD AND UPWARD CENTRIFUGALFLOW OF SAID LIQUID WHEN THE IMPELLER IS ROTATED SO THAT SAID LIQUID ISSPRAYED SUBSTANTIALLY UNIFORMLY FROM THE ENTIRE EXPOSED PERIPHERY